1. Field of the Invention
The present invention relates to a method of designing integrated microcomputers as well as an integrated microcomputer with modular structure obtained by said method.
2. Description of the Related Art
At present each microcomputer is distinguished from the others by the kind and number of functions provided. This means that each time it is desired to add or delete a function it is necessary not only to replace the microcomputer but actually redesign it partially or totally. This implies a long development time for new versions and chances of introducing errors in the reprocessing of parts already tested in previous versions. In practice this increases the cost of the device and limits the number of versions which may be accomplished.
Alternatively there is provided the accomplishment of the largest possible number of functions in a single microcomputer version so as to satisfy as far as possible the need for various classes of applications. This of course involves in many cases an excess of functions compared with the needs of a specific class of applications, making the solution uneconomical and hence in practice narrowing the chances of employment of the microcomputer. In addition, the system is not open to subsequent extension except at the cost of partial or total redesign.
Another alternative calls for accomplishment of a library of independent modules each built so as to minimized the silicon area occupied by the individual module. The various modules thus have uncorrelated forms and sizes and the electrical terminals carrying the signals necessary for the interconnections between the modules are positioned topologically in different ways. This involves a huge waste of silicon area because of the interconnections between the modules and the technical need for obtaining a regular rectangular form of the chip containing all the required modules. In general the total resulting area is more than double that of the active area effectively used by the starting modules. This considerably increases the production cost of the microcomputer and limits the maximum number of functions technically feasable in a single component.